FIELD OF THE INVENTION
The invention relates to a portable tubes flaring device. More particularly the
invention relates to a device and method to hold and conically flare metal
tubes to the required angle in a progressive manner.
BACKGROUND OF THE INVENTION
In the manufacture of compact heat exchangers, helical tube bundles are used.
These tube bundles are made up of helically coiled tubes and has a straight
portion at the start. The starting end of the tube having a length of 10-20 m,
has to be formed to the required conical configuration using portable device/
unit/attachment.
Before making the straight tube into a coil, the following operations need to
be done.
1. The tube is to be held in position by a suitable clamping arrangement.
2. The required conical drift is to be positioned.
3. Powered cylinder (Hydraulic/Pneumatic/electrical) is to be fixed and used.
4. Flaring to the required angle to be done progressively.
The required included conical angle (20°) is much higher than the
conventional 2° included angle given for cone rolling of tube. The conical
tube expanders available in the market do not cater to this requirement. Hence
special conical expanders made with 20° included angle were procured.
These conical expanders coupled with electrically driven shaft, on taking trials
at the shop floor could not take up the load required to deform the tube to the
required angle and length. The three rollers of the conical expander coming in
contact with the inside diameter of the tube on application of torque got stalled
unable to take up the load and any further increase of torque lead to breakage of
rollers only. Also holding the tube manually without allowing it to rotate while
doing cone rolling, was posing problems.
Hence special tube holding and clamping devices, arrangement and tools and
accessories required for tube flaring were custom-designed, developed and
manufactured.
During working, this clamping/holding arrangement, flaring
drifts/accessories need to get accommodated. Also the flaring reaction has to
*be absorbed in the unit itself. For tube flaring, actuated cylinder and power
pack were integrated to the portable tube flaring unit.
Progressive deformation of tube was adopted. Because of higher included
conical angle, flaring could not be completed in single continuous stroke of
drift pin. Unlike the conventional tube expander which rotates, here the drift
pin was made to deform the tube. To facilitate axial movement of drift pin
from the powered cylinder, the drift pin was made from single piece in such a
way that on one side conical taper is there while on the other side a threaded
connection to connect to the hydraulic cylinder was provided. Tube flaring
was done in carefully determined increments/angles of cone. This
incremental flaring was made possible by making progressive incremental
flaring operations. The entire set-up was held
rigidly on a base plate with provisions for clamping the hydraulic cylinder with
the drift pin and the tube to be deformed. Apart from the angle of flaring,
other forming related requirements like smooth transition, tube inside surface
finish and maximum tube ovality requirements were also met.
OBJECTS OF THE INVENTION:
It is therefore an object of the invention to propose a portable metal tube
flaring device and method which is able to carryout metal tube flaring by
clamping and flaring in single set up.
Another object of the invention is to propose a portable metal tube flaring
device and method which is capable to flare tubes in a progressive manner.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig.1 - Schematic diagram of the device with the tube in position during
flaring.
SUMMARY OF THE INVENTION
A portable metal tube flaring device comprising:
a compact base plate (1);
a hydraulic powered cylinder unit (3);
a vertical structure (2) mounted on base plate (1) holding the hydraulic
powered cylinder device (3) by using fasteners (bolts and nuts) (4);
a plurality of clamping units (5) mounted on the base plate (1) holding the
flaring tube (7) in proper position;
wherein in the tube (7), the spacer (8) holding drifting pins (9-14) and the
powered hydraulic cylinder (3) hold in a position as a single unit over base
plate and in one axial direction during application of stroke by the powered
hydraulic cylinder (3) during flaring of tubes incrementally.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF
THE INVENTION
As shown in Fig. 1, the portable flaring unit consists of tube clamping
arrangement, drift pin arrangement and a powered hydraulic unit. The Base
plate (1) holds the hydraulic cylinder (3) in position in the vertical structure (2)
using set of fasteners (4). Apart from providing a stable rigid base to take on
the flaring reaction, the fixture ensures flaring pins (9-14) are in position.
Initially, the straight portion of the tube is gripped using 4 pairs of Clamping
units (5) and fasteners (6). Positioned by spacer (8) and connected to the
hydraulic cylinder (3) on actuation, the hydraulic cylinder facilitates axial
movement of drift pins (9-14). The required stroke given by the cylinder is
transmitted to the drift pin and the position of tube is retained by means of
clamps.
With this fixture the tube (7) is clamped rigidly and incremental deformation
is achieved by actuating the selected drift pin by hydraulic cylinder. Stop/start
is controlled by means of the control available in the powered cylinder and
the markings made in the drift pin.
We claim
1. A portable metal tube flaring device comprising:
- a compact base plate (1);
- a hydraulic powered cylinder unit (3);
- a vertical structure (2) mounted on base plate (1) holding the hydraulic
powered cylinder device (3) by using fasteners (4);
- a plurality of clamping units (5) mounted on the base plate (1) holding
the flaring tube (7) in proper position;
characterized in that the tube (7), the spacer (8) holding drifting pins (9-14)
and the powered hydraulic cylinder (3) hold in a position as a single unit over
base plate (01) and in one axial direction during application of stroke by the
powered hydraulic cylinder (3) during flaring of tubes incrementally.
2. The portable metal tube flaring device as claimed in claim 1 wherein tube
(7) is held in position and one set of fasteners (4) are used to clamp and
hold the hydraulic powered cylinder device (3) on the vertical structure (2).
3. The device as claimed in claim 1 wherein the flaring tube (7) hold in the
base plate (1) by clamping unit (5) and fasteners (6).
4. The device as claimed in claim 1 wherein the powered cylinder (3),
spacer (8) holding the drift pins (9-14) and the tube (7) positioned and
aligned as a single unit over base plate (1).
5. A process for flaring a metal tube by a portable metal tube flaring unit
comprising:
- holding the powered hydraulic cylinder (3) on a vertical structure (2)
by using fasteners (4).
- holding the straight end of the flaring tube (7) on the base plate
structure by clamp unit (5) and fasteners (6) where the alighted tubes,
drift pins and cylinder are put is one axial direction before applying
stroke.
6. The process as claimed in claim 6, wherein the load is applied in
increments Starting with lower cone angle and thereby gradually
increasing the angle.

ABSTRACT

The invention relates to a device for portable incremental metal tube end
flaring in straight end of tubes. To facilitate clamping, sets of clamp pads were used.
A compact base plate was provided to house the powered cylinder and to facilitate
axial movement of drift pins. The flaring set-up was coupled to the base plate so as
to form a compact unit which can take care of the flaring reaction within itself.
From the powered cylinder stroke, the power was transferred to the drift pin shaped
like a cone. The invention further relates to a process of smooth and controlled flaring
of tube with portable tube flaring unit, by suitable locking and positioning of tube.